91 s15 jimmy hard cranking
 

my jimmy with 4.3 tbi has just started acting up, it has always cranked right up without giving it any gas, but now i have to hold it about half way down for it to crank and after warming up it runs pretty well normal maybe idles just a hair low. im thinking it might be something simple like a vacuum leak or dirty sensor or something, just wondering if anyone might have any ideas where i should start.

Re: 91 s15 jimmy hard cranking
 

no check engine light btw.

Re: 91 s15 jimmy hard cranking
 

How long has it been since the fuel filter has been changed, for vacuum leaks you can try and spray around the intake and around the throttle body base. Another possibility could be the fuel pump getting weak but i dont believe tbi needs alot of pressure. Does it have any sort of miss or feels a bit sluggish since you been having the hard starting issue.

Re: 91 s15 jimmy hard cranking
 

about first of the year i had to change fuel tank pump and filter, has no other issues other than have to give it gas to start it vs used to would just turn the key and it would crank. what on these engines makes it idle fast when u crank it?, it no longer does that either so what ever causes that could be the culprit maybe?

Re: 91 s15 jimmy hard cranking
 

What i would do is try to prime your engine about 3 to five times and see if it would start. A fuel pressure gauge would help alot to make sure your at constant pressure. Its seems as if fuel isnt staying pressurized

Re: 91 s15 jimmy hard cranking
 

Check to see if your fuel pressure regulator is leaking, its on the back side of the throttle body. Rebuild kits are cheap about $25.00 at your local parts store and takes about an hour. The hardest part is overcoming the spring pressure and tightening the screws when replacing the diaphragm.

http://www.autozone.com/fuel-deliver...?checkfit=true

https://www.youtube.com/results?sear...+body+rebuild+

Casey